GB1571611A

GB1571611A - Internal combustion engines

Info

Publication number: GB1571611A
Application number: GB27910/76A
Authority: GB
Original assignee: Outboard Marine Corp
Current assignee: Outboard Marine Corp
Priority date: 1976-07-05
Filing date: 1976-07-05
Publication date: 1980-07-16
Also published as: SE7707818L; SE432126B; JPS5311211A; US4162663A; CA1072450A

Description

PATENT SPECIFICATION ( 11) 1571611

( 21) Application No 27910/76 ( 22) Filed 5 July 1976 ( 19) ( 23) Complete Specification filed 5 July 1977 ( 44) Complete Specification published 16 July 1980 ( 51) INT CL 3 F 02 B 25/06 ( 52) Index at acceptance FIB IB 9 1 Gl K 1 GX 15 2 A 11 B 2 A 18 2 A 9 A ( 72) Inventor JOSEPH EHRLICH ( 54) IMPROVEMENTS IN OR RELATING TO INTERNAL COMBUSTION ENGINES ( 71) We, OUTBOARD MARINE CORPORATION, a Body Corporate organised under the laws of the State of Delaware, United States of America, of 100 Seahorse Drive, Waukegan, Illinois 60085, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and

by the following statement: -

This invention relates to internal combustion engines and more particularly to four stroke internal combustion engines, and offers improvements in introducing air to the cylinder of an internal combustion engine during a suction or induction stroke.

According to the invention, an internal combustion engine comprises a cylinder, a piston movable in said cylinder between top dead centre and bottom dead centre positions, an air entry port located in said cylinder immediately above said piston when said piston is at bottom dead centre and adapted to be opened and closed by the piston in response to piston movement, and a reed valve associated with said air entry port for preventing flow through the port from the cylinder and permitting flow through the port to the cylinder.

In a four stroke engine, the arrangement is preferably such that the piston moves to bottom dead centre from a head end of the cylinder, which head end is associated with a main inlet port adapted to be closed as said piston in a suction stroke approaches bottom dead centre It is also possible to have an engine driven pump for presurising the air for entry into the cylinder through an air entry port or ports.

In a preferred form of the invention, the or each air entry port opened by the piston at bottom dead centre is directed generally tangentially of the cylinder, i e is directed to lead inlet air round the cylinder against the inside wall thereof Hence in operation of the engine, air through the said port or ports enters the cylinder with a swirling movement mainly between the indrawn charge and the cylinder wall whereby stratification and turbulence is achieved Conveniently there is an array of air entry ports disposed circumferentially around the cylinder wall and they may open from a local gallery surrounding the cylinder wall and communicating with atmosphere or the outlet of an engine driven pump.

The air entry port or ports are conveniently simply uncovered by the piston on the last part of the induction stroke so that the final piston movement draws the air into the cylinder Alternatively the air can enter under pressure established by a pump, or any other means.

An embodiment of the invention will now be described by way of example and with reference to the acompanying drawings, in which: Figure 1 is a sectional elevation of an engine embodying the invention, and Figure 2 is a sectional view taken along lines 2-2 in Figure 1.

Figure 1 shows how when the piston 11 is approaching bottom dead centre (it is shown in Figure 1 at bottom dead centre) the last movement of the piston on the induction stroke draws air into the cylinder 12 through air entry ports 13 arranged circumferentially around the cylinder wall Figure 2 shows that there are three ports 13 arranged circumferentially around the cylinder wall, and communicating with a surrounding chamber or gallery 14 connected to a source of air at 15 which may merely be the surrounding air or may be the outlet from a means for providing a pressurised flow of air such as a pump driven by the engine Each port 13 is fitted with a reed valve 16 permitting air to enter the cylinder when there is a pressure differential across it but preventing gas from escaping from the cylinder.

The main fuel-air inlet valve 17 is arranged to be closed by its cam 18 as the ports 13 begin to be uncovered.

On the induction stroke the piston draws in fuel/air mixture through the valve 17 which is closed as the piston approaches M F:.

1,571,611 bottom dead centre and starts to uncover the air ports 13 Thus the final movement of the piston draws air in through the ports 13 and their reed valves.

The tangential direction of the ports 13 shown in Figure 2 causes the incoming air to swirl generally as indicated at 19 which produces stratification and turbulence.

On the compression stroke the reed valves prevent escape of charge before the ports 13 are covered, and on the subsequent working stroke even after the ports are uncovered as the piston aproaches bottom dead centre the reed valves 16 will prevent loss of the ignited charge and loss of pressure.

On the exhaust stroke the burnt products of combustion are discharged through the exhaust valve 19 which is suitably opened by its cam 20.

Claims

WHAT WE CLAIM IS:-

1 An internal combustion engine comprising a cylinder, a piston movable in said cylinder between top dead centre and bottom dead centre positions, an air entry port located in said cylinder immediately above said piston when said piston is at bottom dead centre and adapted to be opened and closed by the piston in response to piston movement, and a reed valve associated with said air entry port for preventing flow through the port from the cylinder and permitting flow through the port to the cylinder.

2 An internal combustion engine in accordance with claim 1, wherein said air entry port extends generally tangentially of said cylinder so that air entering said cylinder through said port swirls within said cylinder.

3 An internal combustion engine in accordance with claim 1 or 2 further including an air chamber extending at least partially circumferentially around said cylinder and communicating with a source of air, and a plurality of said air entry ports each with an associated reed valve, said ports being arranged around said cylinder in an angularly spaced series and communicating between said cylinder and said air chamber.

4 An internal combustion engine comprising a cylinder, a piston movable in said cylinder between top dead centre and bottom dead centre positions, a plurality of air entry ports located in said cylinder immediately above said piston when said piston is at bottom dead centre and adapted to be opened and closed by the piston in response to piston movement, said air entry ports being arranged around said cylinder in an angularly spaced series and extending generally tangentially of said cylinder so that air entering said cylinder through said ports swirls within said cylinder, an air chamber extending at least partially circumferentially around said cylinder and communicating with a source of air and with said plurality of air entry ports, and a separate reed valve operatively associated with each of said ports preventing flow from said cylinder to said air chamber and permitting flow into said cylinder from said chamber.

An internal combustion engine in accordance with claim 3 or 4, wherein said source of air comprises means for providing a pressurised flow of air.

6 An internal combustion engine in accordance with any one of the preceding claims, wherein said engine is a four stroke engine.

7 An internal combustion engine in accordance with claim 6, the arrangement being such that said piston moves to bottom dead centre from a head end of the cylinder, which head end is associated with a main inlet port adapted to be closed as said piston in a suction stroke approaches bottom dead centre.

8 An internal combustion engine substantially as hereinbefore described with reference to the accompanying drawings.

ARTHUR R DAVIES, Chartered Patent Agents, 27 Imperial Square, Cheltenham, and High Holborn, London, W C 1.

Agents for the Aplicants.

Printed for Her Majesty's Stationery Office by Burgess & Son (Abingdon), Ltd -1980.

Published at The Patent Office, 25 Southampton Buildings, London, WC 2 A l AY, from which copies may be obtained.

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